Who was allowed to compete in the ancient olympics

Only the man who could speak Greek could  compete in the ancient games otherwise known as the Olympics. Also only man could compete, there was no women who would compete. 

Not everyone in Ancient Greece was eligible to compete in the Olympics. Only Greek and boys, who were free citizens, not criminals, and whose city states agreed to participate in the Olympic truce of the games, were allowed to compete. The truce was written on a bronge discus kept in the Temple of Hera.

The rise of sea levels.

While global warming can affect the Earth in various ways, it cannot raise the levels of water (which includes lakes, oceans, and seas).